What is the name of the first Bitcoin mining pool?

The first Bitcoin mining pool was Slush Pool.

Slush Pool began in November 2010, when Bitcoin mining was becoming difficult enough that individual miners faced increasingly long waits to find blocks. Pooling computing power let participants combine their work and divide rewards according to contributed effort.

The pool was founded by Marek Palatinus, known online as Slush. Its original reward approach became associated with “Slush’s system,” a pooled-mining method that reduced the advantage of joining late in a mining round. The name later became Slush Pool, and the service was eventually operated by Braiins.

A common mix-up is confusing the first pool with later industry leaders such as BTC.com, AntPool, or F2Pool. Those pools became prominent much later; F2Pool, for example, launched in 2013. Slush Pool’s historical importance comes from its early creation, not from being the largest pool today.